There are many medical procedures which employ balloon catheters. In most cases, the length of the balloon must be pre-determined by the clinician prior to selection and insertion of the balloon catheter into the body. For example, in balloon angioplasty, the length of the diseased blood vessel is first determined. Usually, the physician determines in advance the approximate size of the vessel area to be treated. This can be done, for example, through fluoroscopic X-ray, ultrasound imaging, and/or CAT scanning techniques. When balloon length choices are few, a clinician will generally choose a length shorter than the length of the lesion to be treated and will sequentially dilate different portions of the vessel. This extends the time and risks of the procedure. Where several catheters of differing balloon lengths are available the physician will select a balloon length which will cover the entire length of the portion of the vessel requiring dilatation. If two or more blockage sites of different lengths exist within the same artery and the physician determines that two or more different sized balloons must be used, the physician will generally treat the most proximal site first, deflate and withdraw the first balloon catheter, and then insert a second balloon catheter with a different length balloon to treat the second stenotic region. Shorter balloons are often used to dilate lesions located on sharp bends in coronary arteries to prevent straightening and possible damage during the dilatation procedure. Longer balloons are employed to dilate large areas with extensive disease. Changing balloons, however, is a costly, time-consuming and potentially risky procedure that could lead to injury or death of the patient.
In addition, while it is believed the primary use for balloon catheters is for treating profuse disease in blood vessels, and in particular diseased portions of peripheral and coronary arteries, there are certain other procedures where one of a plurality of catheters having different length balloons must be selected. For example, when utilizing a drug eluting balloon, it would be preferable to determine the area of the vessel where a drug is to be delivered and adjust the balloon length accordingly. This will only release the drug in the targeted area and avoid exposing healthy portions of the vessel to the drug. Usually these drugs are toxic to healthy tissue so a targeted approach is desirable.
In addition, what has been needed and heretofore unavailable is a stent delivery device, which allows for a variable length expandable member needed for proper stent deployment and safe and effective sizing of a deployed stent.
Thus, in the foregoing procedures, the physician must have catheters with various sized balloons on hand so that he/she can select the proper size balloon when performing the procedure.
The instant invention obviates the need for having multiple length balloons in a stock room, allows for customizing the length of a balloon to the size of a lesion or stent and provides for targeted delivery of a drug utilizing a drug eluting balloon.